JPH0525321B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to self-propelled vehicles, and particularly to guidance devices for automatic guided vehicles, automobiles, and the like.

[Conventional technology]

As described in Japanese Patent Application Laid-Open No. 59-32009, conventional devices obtain steering signals by measuring the position of an optical tape laid on the road surface using a one-dimensional imaging device.

However, as the wheels of the automatic guided vehicle pass over the optical tape used for guidance, it becomes dirty or torn, requiring replacement. Furthermore, since the travel path of the automatic guided vehicle is generally a path for people, it was often damaged as in the above case.

The damage to this tape cannot be determined visually, so leaving it unattended could cause the automated guided vehicle to derail or stop accidentally.

In other words, no consideration was given to the maintenance of the optical tape.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology does not take into account poor steering due to deterioration of the optical tape, and has problems such as a decrease in the operating efficiency of the automatic guided vehicle.

The purpose of the present invention is to detect deterioration of optical tape in advance and output tape maintenance information.
The aim is to improve the operating efficiency of automated guided vehicles.

[Means for solving problems]

The above object is achieved by examining the amount of light reflected from the optical tape, the width of the tape, and the state of defects inside the tape.

That is, when the tape surface becomes dirty, the amount of reflected light decreases, making it impossible to obtain light exceeding a specified value, and as a result, it becomes impossible to obtain the correct tape width.
Therefore, by examining the amount of reflected light,
You can check whether the tape is dirty or deteriorated.

Furthermore, if the tape becomes damaged, the tape width obtained by the detector may become narrower than a specified value, or holes may occur inside the tape. The object of the present invention can be achieved by examining this state together with the amount of reflected light.

[Effect]

The one-dimensional imaging device for detecting the optical tape is the same as the conventional one, but its signal is input to a comparator for obtaining a signal for steering and a comparator having a reference value higher than that of the comparator. A comparator with a high standard value quickly responds to a decrease in the amount of reflected light from the optical tape, so a decrease in the amount of reflected light can be detected by comparing the output results of the steering comparator and the comparator with a high standard value. be able to.

Further, damage to the tape can be detected by checking the absolute value of the width.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Although FIG. 1 is a block diagram, reflected light from the optical tape is input to an image sensor 1 and converted into an electrical signal. The video amplifier 2 amplifies the output signal of the image sensor and outputs it to the comparators 100 and 200.
Send to. The comparator 100 produces a signal for obtaining a steering signal, and the reference voltage generator 101 is set to a specified value. Comparator 2
00 is for outputting a tape dirt signal, and a reference voltage generator 201 having a higher reference value than the reference voltage generator 101 is connected.

A binary counter is connected to each comparator 100, 200, one of which is a rising binary counter 102 (or 202), and the other is a rising binary counter 103 (or 203).

By passing the output from the video amplifier 2 through the comparator 100, the analog signal number changes from "1" to "0" into a binary signal. The number of times the signal rises is 2
Counting is performed by the advance counter 102. Similarly, the number of falling edges is counted by a falling binary counter 103.

Binary counters 102, 103, 202, 203
Decoders 104, 105, 204, 2 are used for the output of
05 are connected, and these decoders are binary counters 104A~104N, 105A~ that count pulses from the start according to the input signal.
105N, 204A~204N, 205A~20
Controls the operation of 5N.

If a video signal as shown in FIG. 2A is obtained by the image sensor 1, the reference voltage for steering is
When binarized with B', a binary signal like B is obtained. Similarly, if voltage C' is slightly higher than B', a binary signal like C can be obtained.

This binary signal operates rising and falling binary counters 102, 103, 202, 203, and decoders 104, 105, 204, 2
05, the number of pulses from the end becomes 1 in the binary counter.
04A~104N, 105A~105N, 204
It is input to A to 204N and 205A to 205N.

In the example of FIG. 2B, the value on the binary counter 104 side on the rising edge side is represented by the symbol XOS, and the value on the binary counter 105 side on the falling edge side is represented by XOE. Similarly, the example values of C are represented by X'OS and X'OE.

Binary counters 104A~104N, 105A~
105N, 204A~204N, 205A~20
5N is connected to a microcomputer 301 via an interface circuit 300.
The microcomputer 301 reads the value of the counter and checks its contents. That is, a binary counter on the rising edge side (for example, 10
The value of the binary counter 205A on the falling edge side corresponding to 4A) is read, and the difference between the counter values on the falling and rising sides is determined. If this difference is within the specified value, it is recognized as a normal optical tape.

When the optical tape deteriorates, as shown in Figure 2.
The comparison value of B' results in a clean binary signal, but the comparison value of C' results in a binary signal with the tape surface cracked. That is, in the case of C, many numbers with similar rising and falling values and small differences appear.

By checking how much the count value of C rises and falls within the range of values from X2B to X2E of B, it is possible to know the state of tape damage and the degree of deterioration.

In this way, tape deterioration can be determined by checking the count values of the rising edge and falling edge using the two types of comparison values. When determining the deterioration, the microcomputer 301 informs the ground control device of the degraded zone via the transmitter 400, and on the ground, the zone to be maintained is printed out based on the information.

〔Effect of the invention〕

According to the present invention, it is possible to repair the optical tape before the automatic guided vehicle derails or stops abnormally, thereby eliminating the need for daily inspection work and restoration work, and greatly improving operational efficiency. can be achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
The figure is a diagram of signal changes. 1...Image sensor, 2...Video amplifier, 3...
Flock generator, 100, 200... Comparator, 1
01,201...Reference voltage generator, 102,20
2...Rising binary counter, 103,203...Falling binary counter, 104,105,204,2
05...Decoder, 104A to 104N, 105
A~105N, 204A~204N, 205A~
205N...binary counter, 300...interface circuit, 301...microcomputer, 302...ROM, 303...RAM, 40
0...Transmitter.

Claims (1)

[Scope of Claims] 1. In an automatic guided vehicle that guides a vehicle by detecting the position of an optical tape laid on a road surface, a first and a second device input the output of a one-dimensional imaging device that detects the optical tape. The first
the comparator has a higher threshold level than the second comparator, and the number of rising signals of the output of the first comparator;
comprising respective counters for counting the number of falling signals, the number of rising signals of the output of the second comparator;
Each counter is provided to count the number of falling signals, and the difference between the number of rising signals of the first comparator and the number of rising signals of the second comparator is determined by the two counters, and means for determining the difference between the number of falling signals of the first comparator and the number of falling signals of the second comparator using two counters, and means for notifying when the difference is outside a predetermined value. A deterioration detection device for an optical tape for an automatic guided vehicle, characterized by the following.